This grant continues our ongoing research on how placebo effects can be enhanced and provides crucial data on the placebo effect's scientific validity and clinical significance. Our model uses Irritable Bowel Syndrome (IBS) to study the placebo effects elicited by different patient-practitioner contexts. In phase one, 260 patients will be randomized to a 3 week three arm RCT comparing: 1. sham needle treatment (a validated sham acupuncture placebo device) given in the context of a patient-practitioner interaction 'augmented' with positive cognitive, emotional and symbolic interactions, 2. identical sham given within a 'limited' contextual interaction, 3. a no treatment control. The primary question tested is whether the 'nonspecific' effects across the two sham device arms and the no treatment arm behave monotonically in a manner analogous to 'dose dependence' i.e. is 'augmented' arm > 'limited arm' > wait-list natural history. This trial also allows us to answer whether 1. the placebo effect in IBS can be enhanced, i.e., does an 'augmented' placebo intervention elicit a greater placebo effect than a 'limited' placebo intervention and 2. whether the 'limited' placebo intervention elicits a greater placebo effect than natural history arm with any 'non-specific' effects attendant to being in a no-treatment control. To maintain ethical norms, phase two will continue the same context, but sham acupuncture will seamlessly be switched to verum acupuncture to explore acupuncture's efficacy in IBS. In addition, a second parallel qualitative study will follow 27 additional patients (whose outcome data will be excluded from the larger study's analysis) through the same three arms; the study will use interviews to explore the relationships between patients' interpretations and understandings (what anthropologists call 'meaning') of IBS, and their responses to placebo and verum treatment. [unreadable] [unreadable]